Development and performance evaluation of a phantom for dose measurement in radiation blood irradiators

This study developed a specialized alanine-based PMMA phantom replicating the geometry of a 300 mL blood bag to improve dose distribution measurement in blood irradiators. Using precision CNC machining, ten dosimeter slots were positioned at 35 mm intervals to evaluate internal and external dose gradients. Experiments using a Cs-137 irradiator at 25 Gy showed that outside doses (C1–C5) ranged from 25.82 to 31.38 Gy, while inside doses (C6–C10) ranged from 19.93 to 25.71 Gy. The central inside position (C8) showed high accuracy (25.71 ± 0.73 Gy), and the mean error remained within ±3% over repeated trials. These results demonstrate that the developed phantom significantly reduces positioning uncertainty and ensures high reproducibility, satisfying international QA guidelines for blood irradiation.